Electrohydraulic theft preventing device



Nov. 30, 1954 Q R, JAMLSON .2,695,685

I ELECTROHYDRULIC THEFT FREVENTING DEVICE Filed Dec. 20, 1949 mm n f 5 voLA GEA 40 Erin/Aran f /7 Q/i .Ff A? INVENTogz. War/es f2. JEM/waff ATTORNFY United States Patent ELEcTRoHYDRitur-icfTHEFrirREvENTnsG f unvlcr,

t This'tinvention relatesatoftlieftfpreventingdeiticestforuse particularly t upone` motor vehicles aand fait.; is ag; particular object ofethsinventiodto Aprovide 'a'devicet for,thi s;purpose which, `when prepared-for functioning; is initially activated bytheastarting othe-vehicleimotomanddstthen maintained active by -iiuidfundenspressureiin' a tlluid :lineeimwh-ichr the deviceY is v installed.

Another object of the present invention is to provideia motor vehicle theft preventing device which isffdesigned fori` installation rin-a .uid brake$-line Tbetweenthe master cylinder. and .the; fbrakesy or in they gasoline, line -bet-ween the fuel ypump andthe-carburetor,tand hasavalve/ aetuatingelectro-magnet which is ,-coupledfwith a current generator whereby; upon the starting of the 'vehicleengine currentl will becomes-instantly; availablettoactuate the electro-magnet to close t-he'valve andsubsequent actuation of Y the `fluid brake pedal or Vfthe. 'functioning .of the` t fuel pump-willf buildl up., pressure against thefvalvefto maintain the latter closedfeven thoughvthezcurrentmayfbe shutoff by.the--stoppingof1the engine, such action resulting, yin alluid brake `line installation, ,f to4 hold the brakesl applied, and in 'a gasoline lineiinstallation, tov shut olfthez llow of fuellto` the carburetoruntil-the`valveis opened/ by means kn'ownonly` to the t ear-owner or` operaton :Anotherfobject of the invention-,is toprovideanelectrohydraulic motorvehicle ...the'ftQ-.preventingf device of the character stated, which is of fs'mall, .andfsimple constructiontwhereby itcanbe easilyfinserted infa fluid-brakeor a gasolinerlineand -be relatively inconspicuous, -and which isat the same time sturdy and reliable inoperation.4

l Other objects` aridfadvantages of fthe invention Will become `apparent :as"the description off the same, proceeds and the` invention will be bestzunder'stod from` a consideration .of E the following. detailed descriptionVV taken ,inz connection with the accompanyingldrawingjforminga partfof the specification,y 'with' the understanding, however, 'that the invention is `not `to, be limited to Vthe .exactdetails of `construction shownanddescribed since 'obvious modifications will occur to a person skilled in the' art. -Inthed'rawingr "Figure 1 .is a view 'inlongitudinal sectionofan electrohydraulicth'eft 'preventing deviceA constructedinaccordance with the present 'invention and showingtheelectrical between a` fuelpump anda' carburetor, all parts-being'in elevation.

gitudinal section, of a modified formof the invention, de-

signed particularlyV for use infthefgasol'ine line.

The device of the present invention is designed, when used in a motor vehicle, to be placed either in the uid line of a uid brake system or in the gasoline line.

In describing the device its connections will first be set forth as in a fluid brake system where it would be installed between the master cylinder and the brakes.

In Figure l there is shown an end of a pipe 10 which leads from the master cylinder (not shown) of a uid brake system, while the pipe 11 leads to the distribution pipes for the several brakes (not shown).

In accordance with the present invention there is pro- ,vided a metal cylinder 12 of suitable length, the bore 13 ICC A:a of' W117ichiprovides; wcylinderl chamberfortl the` hereinafter describedfpistonfvalve. i

At; onei end fof the'cylinder, hereinafter, for convenience ofdescrip tionand twit-houtintending in any way, to limit the invention, referred to as the head end, an external-reduction 1in diameter-isrmade .as-indicated at ltlyuponwhich reduced A-portiomis fsli'dably, installedaan-electro-magnetic uni-tegenerfallydesignated -15. t

YThis-funit,115fmayybe of-any` suitable form.-andfconstruc tion andtisfhere shown as comprising. the customarycoil onwindings 16T (conventionally illustrated) within afmetal casing- 1 7,clo sed at.` one end f byTa-cap 18, the Vcoilbeirig Ponta-15111001 1,9-

. Thel inside -diameterzof thefspool ,is ,.of, tpropenizel toA snugly#slidablyreceive, e-reducedpart `14` oftthe. cylinder, The coil has an end @leading -fromthecasing .while thetotherfendris gronn'dedetothe casing, such, groundhere' being 'designated-21.

.i -The-headfend ofthe cylinder-,is internally screw "thred-I ed-v as` ,indicatedlat 22 tothreadably= receive thetinner end of acouplingnipplenandf valve seat member, generally designated, 23.

-The outer-,end oftheV memberf23 isenlarged toprovide a head 24, which. engages the; outer-face of .the 'casing cap 1'8, through which the said inner end of `the `inerber extends, thustsecuring `{themagnet on the lcyl-inderas shown.

The nipple fr nerriberhas therethrough the axialbore.` 2 5, inthe outeror head en'd f which' thepip`ef10 isthreaded.

Theinner,endoffthebore 25' is reduced` inidiameter as 4indicated atQ-25aand. `'extends ,-throughf a circular'f boss lupon 'the-innerend of ,thelme'mberZfL `which forms ia (valve seat26.

The end'f the'c'ylinder remote from'the magnet 'is also internallyscrew threadedas indicated at` 27 to receive "a `'threaded endffa coupling"nipp1e128,',thro1gh which is .the bore`f29. 3

' Reciprocbjly,disposedwithin the 'cylinder bore 13'` is a valvepistonunitwhich isgenerally designated 33 and which yisformed of soft iron totfunction as a` movable corelor'jtheelectronagnen V *The nit33 `comprisesl the `head and taildiscs 34 landS respectively connectedl by the :stem36.

AThese'discsareof''a` diameter to fit fairly snuglymin'tthe "bore13 `butatthe` same time be capable of freelsliding movementthere'in.

f'Eachof the discs34-andi35 h ascutacross its periphery Va"nuniber'of recesses- 34a-fand 35a respectively through whicl'uid tn ay pass-from Ione side; or end, of-'the valve unittto the other:under,'certain conditionsof operationof "theidevice `In the forwardiface, or headfacefofl-the-:diso34,is fixedv a valve'sealzor-i button 37, Awhichmayfbe -made of l=this` pocket extends" apin39. The other; G11-forward, -end 'of the spring 32 eittexidsintothe pocket 381a'r'1d Vis attached tothe pin 39, as shown.

The sp'ring' `lig'jnorn'ially holds the' `piston' valve unitv 3 3, retracted f ronj1"- thei nipple `me `rnber.2 3, so" that the Jvalve seal37-is-offofthe seat'2'6, and,also,the forward disc 34 only is part way within the central or core portion of the magnet coil.

When the magnet coil has electric current passed therethrough, it is energized, the unit 33 is drawn forwardly against the resistance of the spring 32 and the seal 37 is firmly pressed upon the seat 26.

When the device is installed in a uid brake line as shown, and described, the terminal Z0 of the magnet is connected, through a suitable switch 40 with the eld terminal F of the voltage regulator R. This terminal is connected in the current generator system with the eld coil 41 of the generator G; The regulator R and the generator connections shown, are standard hook-up in motor vehicle electrical systems and do not require further description.

The switch 4@ may be of any character to be set or closed manually when the car, in which the theft preventer device is installed, is left by the operator and is to be secreted in some place not readily found by a car thief.

In operation, when the car motor is started by an unauthorized person, the switch 40 being closed, the electromagnet coil will be energized at once upon the starting of the generator. This will pull the piston valve forwardly against the tension of the spring 32, to close the small end 25a of the bore 25, which will be kept closed so long as the motor continues to run. The car can, of course, be started and run until it becomes necessary tor the thief to apply the brakes. When the brakes are applied sucient pressure will be applied to the valve seal or butt-on 37 to unseat it sufficiently for the fluid to be forced through to the car brakes. Thus the brake Huid will be put under high pressure between the theft prf Venter device and the car brakes and when the pressure is relieved slightly in the pipe 10, or is held steady, the energized magnet coil will pull the unit 33 back to its former position, to close the bore 25. The fluid under pressure vwill thus be trapped between the pressure surfa-ces of the unit 33 and the brakes, preventing the brakes from being released.

The thief cannot then again start the vehicle and even though the motor may be stopped, thus deenergizing the coil, the trapped fluid will hold the unit 33 seated.

The areas of the faces of the discs 34 and 35 which are exposed to the pressure of the fluid equals the cross sectional area of the stem 36 so that suicient pressure is impressed, in the proper direction, on the unit to hold it tightly seated against the pulling action of the Spllng.

When the owner of the car wishes to start it after the theft preventer has functioned as described, he can release the locked brakes by applying pressure against the unit 33, by depressing the brake pedal, until such applied pressure equals the opposing pressure against the rearward sides of the discs 34 and 35 whereupon the spring may become effective to pull the unit away from the seat 26. If the switch 40 is then opened, or it may have been previously opened, the engine can be started without affecting the coil and valve unit, and be operated as usual.

With the hook-up of the theft preventer device in the gasoline line between the fuel pump P and the carburetor C, as shown in Figure 4, its operation is the same as just described. However, as will be readily apparent the vehicle may be run for a short distance and it may be stopped and started but this can continue only as long f as the gasoline supply in the curburetor oat chamber holds out. As soon as the engine is started the energized coil 16 will pull the piston valve unit 33 to the seat 26 and the fuel pump will then build up pressure against the unit which will hold the unit tightly seated to close off the pipeline a leading to the carburetor.

When the engine has stopped for lack of fuel and the switch opened, no fuel can be got through to the carburetor until the nipple 23 is backed out to such an extent that the pressure in the pipe 11a and the valve unit chamber 13 is reduced to the point where the spring 32 is able to retract the unit.

Figure 5 illustrates a modified form of the invention, for use in the gasoline line, designed to eliminate the spring 32, shown in the first form.

In this modified structure the electro-magnet unit is the same as in the first form and is designated 15a.

The cylinder 12a has the magnet removably held on one end by the coupling nipple 23a, with which is connectedthe pipe 10b,1eading to the carburetor. f Y

The cylinder is modified by having the end remote from the magnet, closed by the wall 12b, and the pipe line (not shown) which leads from the fuel pump is connected to the cylinder, by the nipple 28a, which is threaded in the side Wall of the cylinder, as shown.

This modified embodiment of the valve is mounted for use with the cylinder upright and the valvepiston unit 33a, normally is positioned with one end disc 35 resting upon the end wall 12b, the other disc 34 being located above the inlet end of the nipple 28a. t d

With this construction the valve piston unit 33a will tend always to move downwardly in the cylinder or away from the fluid outlet nipple 23a, as it does in the first embodiment under the action ofthe spring 32, and the line pressure from the fuel pump will tend to hold the valve olf of its seat.

From the foregoing it will be seen that there has been provided 'by the present invention a novel theft preventing device which may be made of small size to` be conveniently installed in either of the locations stated and which will function efficiently to accomplish the desired objects. Thedevice is also relatively simple in construction and may therefore be economically manufactured and sold.

l iclaim:

`In a theft preventing device for connection in the iluid pressure conduit of the hydraulic brake system of an vautomobile hav-ing an electric generator, a tubular member, nipples threaded inwardly of the ends of said member for the coupling of adjacent ends of the conduit to the member, the nipple through which the fluid passes to the member and the brake system has its inner end inwardly thickened to provide a restricted passage therethrough, a bossed valve seat formed on the inner end of the one nipple about said restricted passage, an elongated valve element Within said member and having circular enlargements at each of its `ends, said enlargements -having their peripheries notched for the passage of the uid about the same, the face of the enlargement opposed to said valve seat being centrally recessed, a compressible disk seated in said recess, a pin extending diarnetrically across the passage through the other of said nipples, a contractile spring interposed between said pin and the opposed end of said valve element and acting to hold the latter positioned for the free ow of the fluid through the member and the nipples, an electro-magnetic coil mounted on said member in encircling relation with respect to the opposed end portions of said one nipple and of the valve element, and a secreted switch connected in circuit with said coil and the electric current generator of the automobile to control the energizing and deener gizing of said coil, said valve element being in open position when the brakes are applied to bring the automobile to a stop, said coil, when energized by lt'he closing of said switch, acting to close said valve element on said valve seat to trap the uid and thereby maintain the brakes applied until the switch is again opened by the authorized operator of the automobile.

References Cited in the file of this patent UNITED STATES PATENTS Ashton et al. Mar. 28, 1950 

